Scientific Results

Second sound in a two-dimensional Bose gas: From the weakly to the strongly interacting regime

Year: 2018

Authors: Ota M., Stringari S.

Autors Affiliation: [Ota, Miki] Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy;
Univ Trento, Dipartimento Fis, I-38123 Povo, Italy.

Abstract: Using Landau’s theory of two-fluid hydrodynamics, we investigate first and second sounds propagating in a two-dimensional (2D) Bose gas. We study the temperature and interaction dependence of both sound modes and show that their behavior exhibits a deep qualitative change as the gas evolves from the weakly interacting to the strongly interacting regime. Special emphasis is placed on the jump of both sounds at the Berezinskii-Kosterlitz-Thouless transition, caused by the discontinuity of the superfluid density. We find that the excitation of second sound through a density perturbation becomes weaker and weaker as the interaction strength increases as a consequence of the decrease in the thermal expansion coefficient. Our results could be relevant for future experiments on the propagation of sound on the Bose-Einstein condensate (BEC) side of the BCS-BEC crossover of a 2D superfluid Fermi gas.

Journal/Review: PHYSICAL REVIEW A

Volume: 97 (3)      Pages from: 033604-1  to: 033604-7

KeyWords: Einstein condensate; Fermi gas; superfluidity; vortices; systems
DOI: 10.1103/PhysRevA.97.033604

Citations: 5
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-06-28
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